DOT 5 and silicone ****

Do NOT use DOT5, this is Silicone based. Reccommended is DOT4, or DOT 5.1 as these are a grycol base. Silicone (DOT5) i would stay well away from it.

AusRSV said:

Do NOT use DOT5, this is Silicone based. Reccommended is DOT4, or DOT 5.1 as these are a grycol base. Silicone (DOT5) i would stay well away from it.

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Agreed. Sorry mate, looks like you're going to have to drain, then bleed those brakes again. you'll be really good at it when you've finally finished:devious

I have come across this scenario many times whilst working with TVR.

The braking system and clutch release set up was hydraulic and recommended dot5 for race and track conditions.

Customers quite often did track days and used to request that their clutch and brakes be converted to Dot5 so that it didn't boil away and become useless on the track. (Wishful thinking for some TVR owners)

Many would say that once a hydraulic system has had Dot4 then you must not use Dot5 in it as the seals will fail.

Well, all I can say is that in all the time I spent working on TVR's I never saw any evidence of the seals being destroyed by the fluid. Many seals failed prematurely but given the operating conditions e.g. Track events and racing. It was only to be expected.

The only thing we had to do to convert was to ensure we did a full and thorough flush so that the two fluids never mixed.

We drained the system down by using a vacuum, this ensured that no Dot4 was left in the system then we reverse filled it.

My only point to be aware of is that Dot5 absorbs moisture at a faster rate than any other and will therefore need changing a lot more frequently. Failing to change the fluid every 4 months or sooner will result in your brake and clutch efficiencies becoming impaired.

My advise is to stick with Dot4, more than man enough for anyone on the road and possibly track use too. That is unless your a SBK or MotoGP god.

I've always used DOT4, do a few trackdays a year and never had any issues.
I'm no Rossi by anyones standards but can turn some respectable times and being a right fat git will work my brakes harder than most!!

part of the reason for not mixing is not the fact it wrecks the seals but where the 2 meet they can turn into a kind of jelly. I doubt there is much dot4 left in there if it was drained but generally mixing the 2 is not advisable.

Drainig and changing i think you would get away with.